Brush composition and method of producing structure containing phase-separated structure

ABSTRACT

A brush composition used for phase-separation of a layer containing a block copolymer on a substrate, the brush composition including a resin component (N), the resin component (N) containing a hydrophobic structural unit (Nx) and a hydrophilic structural unit (Ny), the amount of the structural unit (Ny) within the resin component (N) being 5 mol % or less.

TECHNICAL FIELD

The present invention relates to a brush composition, and a method ofproducing a structure containing a phase-separated structure.

Priority is claimed on Japanese Patent Application No. 2014-246801,filed Dec. 5, 2014, the content of which is incorporated herein byreference.

DESCRIPTION OF RELATED ART

Recently, as further miniaturization of large scale integrated circuits(LSI) proceeds, a technology for processing a more delicate structure isdemanded. In response to such demand, technical developments have beenconducted on forming a fine structure using a phase-separated structureformed by self-assembly of block polymers having mutually incompatibleblocks bonded together.

For using a phase separation of a block copolymer, it is necessary toform a self-organized nano structure by a microphase separation only inspecific regions, and arrange the nano structure in a desired direction.

For realizing position control and orientational control of suchself-assembled structure, methods such as graphoepitaxy to controlphase-separated pattern by a guide pattern and chemical epitaxy tocontrol phase-separated pattern by difference in the chemical state ofthe substrate are proposed (see, for example, Non-Patent Document 1).

As a method of phase-separating a block copolymer to form a finepattern, for example, there is disclosed a method in which anintermediate layer having a surface free energy of a mean value of thesurface free energy of 2 block chains is formed on a substrate, suchthat the face of the substrate contacting the block copolymer has asurface free energy of a mean value of the surface free energy of 2block chains (for example, see Patent Literature 1). By forming such anintermediate layer on the substrate, the face of the substratecontacting the block copolymer has a surface free energy of a mean valueof the surface free energy of 2 block chains.

In this manner, patterns of various shapes with smaller sizes can beformed as compared to conventional lithography properties.

DOCUMENTS OF RELATED ART Patent Literature

[Patent Document 1] Japanese Unexamined Patent Application, FirstPublication No. 2008-36491

Non-Patent Documents

[Non-Patent Document 1] Proceedings of SPIE (U.S.), vol. 7637, pp.76370G-1 (2010)

SUMMARY OF THE INVENTION

However, in the method disclosed in Patent Literature 1, it wasnecessary to select a neutralization layer material which exhibit asurface free energy of predetermined value, depending on the kind ofblock copolymer used, so as to control the surface free energy of theneutralization layer. Therefore, there were demands for brushcomposition which can be used conveniently.

Further, conventional neutralization layer materials (brushcompositions) had problems that it was difficult to control the surfacestate of the neutralization layer formed, and the phase separation ofthe block copolymer is likely to become poor.

The present invention takes the above circumstances into consideration,with an object of providing a brush composition which can improve thephase-separation performance of a block copolymer and can beconveniently used; and a method of producing a structure containing aphase-separated structure using the brush composition.

As a result of the studies of the present inventors, the presentinventors have found that, when a fine structure is formed by directedself assembly (DSA) of a block copolymer, by improving the adhesion ofthe substrate and the layer containing a block copolymer formed on thesubstrate, the phase-separation of the block copolymer is promoted. As aresult of further studies, the present inventors have found that, byadopting a specific resin component in the brush composition which canenhance the adhesiveness, the surface of the brush layer can becontrolled to be at a highly hydrophobic state. The present inventionhas been completed based on this finding.

Specifically, a first aspect of the present invention is a brushcomposition used for phase-separation of a layer containing a blockcopolymer on a substrate, the brush composition including a resincomponent (N), the resin component (N) containing a hydrophobicstructural unit (Nx) and a hydrophilic structural unit (Ny), the amountof the structural unit (Ny) within the resin component (N) being 5 mol %or less.

A second aspect of the present invention is a method of producing astructure containing a phase-separated structure, the method including:a step of applying the brush composition of the first aspect to form alayer of the brush composition; a step of forming a layer containing ablock copolymer on the layer of the brush composition; and a step ofphase-separating the layer containing the block copolymer.

In the present description and claims, the term “aliphatic” is arelative concept used in relation to the term “aromatic”, and defines agroup or compound that has no aromaticity.

The term “alkyl group” includes linear, branched or cyclic, monovalentsaturated hydrocarbon, unless otherwise specified.

The term “alkylene group” includes linear, branched or cyclic, divalentsaturated hydrocarbon, unless otherwise specified. The same applies forthe alkyl group within an alkoxy group.

A “halogenated alkyl group” is a group in which part or all of thehydrogen atoms of an alkyl group is substituted with a halogen atom.Examples of the halogen atom include a fluorine atom, a chlorine atom, abromine atom and an iodine atom.

A “fluorinated alkyl group” or a “fluorinated alkylene group” is a groupin which part or all of the hydrogen atoms of an alkyl group or analkylene group have been substituted with a fluorine atom.

The term “structural unit” refers to a monomer unit that contributes tothe formation of a polymeric compound (resin, polymer, copolymer).

A “structural unit derived from an acrylate ester” refers to astructural unit that is formed by the cleavage of the ethylenic doublebond of an acrylate ester.

An “acrylate ester” refers to a compound in which the terminal hydrogenatom of the carboxy group of acrylic acid (CH₂═CH—COOH) has beensubstituted with an organic group.

The acrylate ester may have the hydrogen atom bonded to the carbon atomon the α-position substituted with a substituent. The substituent(R^(α)) with which the hydrogen atom bonded to the carbon atom at theα-position is substituted is an atom other than the hydrogen atom or agroup, and examples thereof include an alkyl group having from 1 to 5carbon atoms, a halogenated alkyl group having from 1 to 5 carbon atoms,and a hydroxyalkyl group. A carbon atom on the α-position of an acrylateester refers to the carbon atom bonded to the carbonyl group, unlessspecified otherwise.

Hereafter, an acrylate ester having the hydrogen atom bonded to thecarbon atom on the α-position substituted with a substituent issometimes referred to as “α-substituted acrylate ester”. Further,acrylate esters and α-substituted acrylate esters are collectivelyreferred to as “(α-substituted) acrylate ester”.

A “structural unit derived from hydroxystyrene or a hydroxystyrenederivative” refers to a structural unit that is formed by the cleavageof the ethylenic double bond of hydroxystyrene or a hydroxystyrenederivative.

The term “hydroxystyrene derivative” includes compounds in which thehydrogen atom at the α-position of hydroxystyrene has been substitutedwith another substituent such as an alkyl group or a halogenated alkylgroup; and derivatives thereof. Examples of the derivatives thereofinclude hydroxystyrene in which the hydrogen atom of the hydroxy grouphas been substituted with an organic group and may have the hydrogenatom on the α-position substituted with a substituent; andhydroxystyrene which has a substituent other than a hydroxy group bondedto the benzene ring and may have the hydrogen atom on the α-positionsubstituted with a substituent. Here, the α-position (carbon atom on theα-position) refers to the carbon atom having the benzene ring bondedthereto, unless specified otherwise.

As the substituent which substitutes the hydrogen atom on the α-positionof hydroxystyrene, the same substituents as those described above forthe substituent on the α-position of the aforementioned α-substitutedacrylate ester can be mentioned.

A “structural unit derived from vinylbenzoic acid or a vinylbenzoic acidderivative” refers to a structural unit that is formed by the cleavageof the ethylenic double bond of vinylbenzoic acid or a vinylbenzoic acidderivative.

The term “vinylbenzoic acid derivative” includes compounds in which thehydrogen atom at the α-position of vinylbenzoic acid has beensubstituted with another substituent such as an alkyl group or ahalogenated alkyl group; and derivatives thereof. Examples of thederivatives thereof include benzoic acid in which the hydrogen atom ofthe carboxy group has been substituted with an organic group and mayhave the hydrogen atom on the α-position substituted with a substituent;and benzoic acid which has a substituent other than a hydroxy group anda carboxy group bonded to the benzene ring and may have the hydrogenatom on the α-position substituted with a substituent. Here, theα-position (carbon atom on the α-position) refers to the carbon atomhaving the benzene ring bonded thereto, unless specified otherwise.

The term “styrene” is a concept including styrene and compounds in whichthe hydrogen atom at the α-position of styrene is substituted with othersubstituent such as an alkyl group and a halogenated alkyl group.

A “structural unit derived from styrene” or “structural unit derivedfrom a styrene derivative” refers to a structural unit that is formed bythe cleavage of the ethylenic double bond of styrene or a styrenederivative.

As the alkyl group as a substituent on the α-position, a linear orbranched alkyl group is preferable, and specific examples include alkylgroups of 1 to 5 carbon atoms, such as a methyl group, an ethyl group, apropyl group, an isopropyl group, an n-butyl group, an isobutyl group, atert-butyl group, a pentyl group, an isopentyl group and a neopentylgroup.

Specific examples of the halogenated alkyl group as the substituent onthe α-position include groups in which part or all of the hydrogen atomsof the aforementioned “alkyl group as the substituent on the α-position”are substituted with halogen atoms. Examples of the halogen atom includea fluorine atom, a chlorine atom, a bromine atom and an iodine atom, anda fluorine atom is particularly desirable.

Specific examples of the hydroxyalkyl group as the substituent on theα-position include groups in which part or all of the hydrogen atoms ofthe aforementioned “alkyl group as the substituent on the α-position”are substituted with a hydroxy group. The number of hydroxy groupswithin the hydroxyalkyl group is preferably 1 to 5, and most preferably1.

The case of describing “may have a substituent” includes both of thecase where the hydrogen atom (—H) is substituted with a monovalent groupand the case where the methylene group (—CH₂—) is substituted with adivalent group.

The term “exposure” is used as a general concept that includesirradiation with any form of radiation.

By the brush composition of the present invention, the phase-separationperformance of the block copolymer can be enhanced, and the brushcomposition can be conveniently used.

By the method of producing a structure containing a phase-separatedstructure according to the present invention, the phase-separationperformance of the block copolymer can be enhanced, and a fine structurewith a good shape can be formed, as compared to conventional lithographytechniques.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram showing an example of one embodiment ofthe method of forming a structure containing a phase-separated structureaccording to the present invention.

FIG. 2 is an explanatory diagram showing an example of one embodiment ofan optional step.

DETAILED DESCRIPTION OF THE INVENTION

<<Brush Composition>>

The present invention is a brush composition used for phase-separationof a layer containing a block copolymer on a substrate, the brushcomposition including a resin component (N), the resin component (N)containing a hydrophobic structural unit (Nx) and a hydrophilicstructural unit (Ny), the amount of the structural unit (Ny) within theresin component (N) being 5 mol % or less.

(Block Copolymer)

A block copolymer is a polymeric compound in which plurality of partialconstitutional components (blocks) in which the same kind of structuralunit is repeatedly bonded are bonded. In the present invention,polymeric compound in which a hydrophobic polymer block (b11) and ahydrophilic polymer block (b21) bonded together may be preferably usedas the block copolymer.

The hydrophobic polymer block (b11) (hereafter, referred to simply as“block (b11)”) refers to a block in which, when a plurality of monomershaving different affinity relative to water are used, a monomer whichexhibits relatively low affinity for water among the plurality ofmonomers is polymerized to form a polymer (hydrophobic polymer) as theblock. The hydrophilic polymer block (b21) (hereafter, referred tosimply as “block (b21)”) refers to a block in which a monomer whichexhibits relatively high affinity for water among the plurality ofmonomers is polymerized to form a polymer (hydrophilic polymer) as theblock.

The block (b11) and the block (b21) are not particularly limited as longas long as they are combinations capable of causing phase separation.However, it is preferable to use a combination of blocks which aremutually incompatible.

Further, as the block (b11) and the block (b21), it is preferable to usea combination in which a phase of at least one block amongst theplurality of blocks constituting the block copolymer can be reliablyremoved as compared to the phases of other blocks.

As the blocks constituting the block copolymer, 2 kinds of blocks may beused, or 3 or more kinds of blocks may be used.

In the present invention, the block copolymer may have a partialconstitutional component (block) other than the block (b11) and theblock (b21) bonded.

Examples of the block (b11) and the block (b21) include a block in whichstructural units derived from styrene or a styrene derivative arerepeatedly bonded; a block in which structural units derived from anacrylate ester which may have the hydrogen atom bonded to the carbonatom on the α-position substituted with a substituent (structural unitsderived from (α-substituted) acrylate ester) are repeatedly bonded; ablock in which structural units derived from acrylic acid which may havethe hydrogen atom bonded to the carbon atom on the α-positionsubstituted with a substituent (structural units derived from(α-substituted) acrylic acid) are repeatedly bonded; a block in whichstructural units derived from siloxane or a derivative thereof arerepeatedly bonded; a block in which structural units derived from analkyleneoxide are repeatedly bonded; and a block in which silsesquioxanestructure-containing structural units are repeatedly bonded.

Examples of styrene derivatives include styrene, styrene in which thehydrogen atom on the α-position has been substituted with an alkyl groupor a halogenated alkyl group, or derivatives thereof. Examples of suchderivatives include styrene in which the hydrogen atom on the α-positionmay be substituted and has a substituent bonded to the benzene ring.Examples of the substituent include an alkyl group of 1 to 5 carbonatoms, a halogenated alkyl group of 1 to 5 carbon atoms and ahydroxyalkyl group.

Specific examples of styrene derivatives thereof includeα-methylstyrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene,4-t-butylstyrene, 4-n-octylstyrene, 2,4,6-trimethylstyrene,4-methoxystyrene, 4-t-butoxystyrene, 4-hydroxystyrene, 4-nitrostyrene,3-nitrostyrene, 4-chlorostyrene, 4-fluorostyrene, 4-acetoxyvinylstyrene,and 4-vinylbenzylchloride.

Examples of (α-substituted) acrylate ester include an acrylate ester inwhich the hydrogen atom bonded to the carbon atom on the α-position issubstituted with a substituent. Examples of the substituent include analkyl group of 1 to 5 carbon atoms, a halogenated alkyl group of 1 to 5carbon atoms and a hydroxyalkyl group.

Specific examples of the (α-substituted) acrylate ester include acrylateesters such as methyl acrylate, ethyl acrylate, propyl acrylate, n-butylacrylate, t-butyl acrylate, cyclohexyl acrylate, octyl acrylate, nonylacrylate, hydroxyethyl acrylate, hydroxypropyl acrylate, benzylacrylate, anthracene acrylate, glycidyl acrylate,3,4-epoxycyclohexylmethane acrylate, and propyltrimethoxysilaneacrylate; and methacrylate esters such as methyl methacrylate, ethylmethacrylate, propyl methacrylate, n-butyl methacrylate, t-butylmethacrylate, cyclohexyl methacrylate, octyl methacrylate, nonylmethacrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate,benzyl methacrylate, anthracene methacrylate, glycidyl methacrylate,3,4-epoxycyclohexylmethane methacrylate, and propyltrimethoxysilanemethacrylate.

Examples of (α-substituted) acrylic acid include acrylic acid in whichthe hydrogen atom bonded to the carbon atom on the α-position issubstituted with a substituent. Examples of the substituent include analkyl group of 1 to 5 carbon atoms, a halogenated alkyl group of 1 to 5carbon atoms and a hydroxyalkyl group.

Examples of (α-substituted) acrylic acid include acrylic acid andmethacrylic acid.

Examples of siloxane and siloxane derivatives include dimethylsiloxane,diethylsiloxane, diphenylsiloxane, and methylphenylsiloxane.

Examples of the alkylene oxide include ethylene oxide, propylene oxide,isopropylene oxide and butylene oxide.

As the silsesquioxane structure-containing structural unit, polyhedraloligomeric silsesquioxane structure-containing structural unit ispreferable. As a monomer which provides a polyhedral oligomericsilsesquioxane structure-containing structural unit, a compound having apolyhedral oligomeric silsesquioxane structure and a polymerizable groupcan be mentioned.

In the present invention, examples of the block copolymer include apolymeric compound in which a block having structural units derived fromstyrene or a styrene derivative repeatedly bonded, and a block havingstructural units derived from an (α-substituted) acrylate esterrepeatedly bonded, are bonded together; a polymeric compound in which ablock having structural units derived from styrene or a styrenederivative repeatedly bonded, and a block having structural unitsderived from an (α-substituted) acrylic acid repeatedly bonded, arebonded together; a polymeric compound in which a block having structuralunits derived from styrene or a styrene derivative repeatedly bonded,and a block having structural units derived from siloxane or aderivative thereof repeatedly bonded, are bonded together; a polymericcompound in which a block having structural units derived fromalkyleneoxide repeatedly bonded, and a block having structural unitsderived from an (α-substituted) acrylate ester repeatedly bonded, arebonded together; a polymeric compound in which a block having structuralunits derived from alkyleneoxide repeatedly bonded, and a block havingstructural units derived from an (α-substituted) acrylic acid repeatedlybonded, are bonded together; a polymeric compound in which a blockhaving structural units derived from having a polyhedral oligomericsilsesquioxane structure repeatedly bonded, and a block havingstructural units derived from an (α-substituted) acrylate esterrepeatedly bonded, are bonded together; a polymeric compound in which ablock having structural units derived from having a polyhedraloligomeric silsesquioxane structure repeatedly bonded, and a blockhaving structural units derived from (α-substituted) acrylic acidrepeatedly bonded, are bonded together; and a polymeric compound inwhich a block having structural units derived from structural unitsderived from having a polyhedral oligomeric silsesquioxane structurerepeatedly bonded, and a block having structural units derived fromsiloxane or a derivative thereof repeatedly bonded, are bonded together.

Among these examples, as the block copolymer, a polymeric compound inwhich a block having structural units derived from styrene or a styrenederivative repeatedly bonded, and a block having structural unitsderived from an (α-substituted) acrylate ester repeatedly bonded, arebonded together; or a polymeric compound in which a block havingstructural units derived from styrene or a styrene derivative repeatedlybonded, and a block having structural units derived from an(α-substituted) acrylic acid repeatedly bonded, are bonded together ispreferable; a polymeric compound in which a block having structuralunits derived from styrene or a styrene derivative repeatedly bonded,and a block having structural units derived from an (α-substituted)acrylate ester repeatedly bonded, are bonded together is morepreferable; and a polymeric compound in which a block having structuralunits derived from styrene or a styrene derivative repeatedly bonded,and a block having structural units derived from a (meth)acrylate esterrepeatedly bonded, are bonded together is still more preferable.

Specific examples thereof include a polystyrene-polymethyl methacrylate(PS-PMMA) block copolymer, a polystyrene-polyethyl methacrylate blockcopolymer, a polystyrene-(poly-t-butyl methacrylate) block copolymer, apolystyrene-polymethacrylic acid block copolymer, apolystyrene-polymethyl acrylate block copolymer, a polystyrene-polyethylacrylate block copolymer, a polystyrene-(poly-t-butyl acrylate) blockcopolymer, and a polystyrene-polyacrylic acid block copolymer. Amongthese, a PS-PMMA block copolymer is most preferable.

The weight average molecular weight (Mw) (the polystyrene equivalentvalue determined by gel permeation chromatography) of each polymerconstituting the block copolymer is not particularly limited as long asit is large enough to cause phase separation. The weight averagemolecular weight is preferably 5,000 to 500,000, more preferably 5,000to 400,000, and still more preferably 5,000 to 300,000.

The weight average molecular weight (Mw) of the block copolymer is notparticularly limited as long as it is large enough to cause phaseseparation. The weight average molecular weight is preferably 5,000 to100,000, more preferably 20,000 to 60,000, and still more preferably30,000 to 50,000.

The polydispersity (Mw/Mn) of the block copolymer is preferably 1.0 to3.0, more preferably 1.0 to 1.5, and still more preferably 1.0 to 1.2.Here, Mn is the number average molecular weight.

The period of the block copolymer (the length of 1 molecule of the blockcopolymer) is preferably 5 to 50 nm, more preferably 10 to 40 nm, andstill more preferably 20 to 30 nm.

In the present specification, a “period of a block copolymer” refers toa period of a phase structure observed when a phase-separated structureis formed, and is a sum of the lengths of the phases which are mutuallyincompatible. Specifically, in the case of forming a cylinder structurewhich has a phase-separated structure perpendicular to a surface of asubstrate, the period of the block copolymer is the center distance(pitch) of two mutually adjacent cylinder structures.

The period of a block polymer is determined by intrinsic polymerizationproperties such as the polymerization degree N and the Flory-Hugginsinteraction parameter χ. Specifically, the repulsive interaction betweendifferent block components of the block copolymer becomes larger as theχN becomes larger. Therefore, when χN>10 (hereafter, referred to as“strong segregation limit”), there is a strong tendency for the phaseseparation to occur between different blocks in the block copolymer. Atthe strong segregation limit, the period of the block copolymer isapproximately N^(2/3)χ^(1/6). That is, the period of the block copolymeris in proportion to the polymerization degree N which correlates withthe molecular weight Mn and molecular weight ratio between differentblocks. Therefore, by adjusting the composition and the total molecularweight of the block copolymer to be used, the period of the blockcopolymer can be adjusted.

<<Resin Component (N)>>

The brush composition according to a first aspect of the presentinvention includes a resin component (N), the resin component (N)containing a hydrophobic structural unit (Nx) and a hydrophilicstructural unit (Ny), the amount of the structural unit (Ny) within theresin component (N) being 5 mol % or less.

The hydrophobic structural unit (Nx) (also referred to as “hydrophobicpolymer block (Nx)”; hereafter, referred to simply as “block (Nx)”) is ablock constituted of a polymer (hydrophobic polymer) obtained bypolymerizing a monomer which exhibits relatively low affinity for wateras compared to a monomer which provides a structural unit of thehydrophilic polymer block (b21) constituting the block copolymer. Thestructural unit of the block (Nx) and the structural unit of the block(11) may have the same structure, or different structures. Since theadhesion of the substrate to the layer containing a block copolymer viathe brush layer becomes strong, the structural unit of the block (Nx)and the structural unit of the block (b11) preferably have the samestructure.

The hydrophilic polymer block (Ny) (also referred to as “hydrophilicpolymer block (Ny)”; hereafter, referred to simply as “block (Ny)”) is ablock constituted of a polymer (hydrophilic polymer) obtained bypolymerizing a monomer which exhibits relatively low affinity for wateras compared to a monomer which provides a structural unit of thehydrophobic polymer block (b11) constituting the block copolymer. Thestructural unit of the block (Ny) and the structural unit of the block(b21) may have the same structure, or different structures.

Examples of the block (Nx) include a block in which structural unitsderived from styrene or a styrene derivative are repeatedly bonded.

Examples of the block (Ny) include a block in which structural unitsderived from an (α-substituted) acrylate ester are repeatedly bonded; ablock in which structural units derived from an (α-substituted) acrylicacid are repeatedly bonded; a block in which structural units derivedfrom siloxane or a derivative thereof are repeatedly bonded; a block inwhich structural units derived from an alkyleneoxide are repeatedlybonded; and a block in which silsesquioxane structure-containingstructural units are repeatedly bonded.

Styrene or styrene derivative, the (α-substituted) acrylate ester, the(α-substituted) acrylic acid, siloxane or derivative thereof, thealkyleneoxide and the monomer which provides a silsesquioxanestructure-containing structural unit for the block (Nx) and the block(Ny) are the same as defined for the examples of compounds described forthe block (b11) and the block (b21).

In the present invention, the amount of the structural unit (Ny) withinthe resin component (N) is 5 mol % or less. The amount of the structuralunit (Ny) is preferably 4 mol % or less, and more preferably 3 mol % orless.

In the resin component (N), the amount of the structural unit (Ny) ispreferably 0.1 mol % or more, ore preferably 0.5 mol % or more, and mostpreferably 0.7 mol % or more.

The above upper limits and lower limits can be arbitrarily combined.

In the brush composition of the present invention, by virtue of thespecific amount of the structural unit (Ny), when a brush layer isformed using the brush composition of the present invention, it isconsidered that the surface of the brush layer can be controlled to ahighly hydrophobic state.

Structural Unit (Nx)

In the present invention, the structural unit (Nx) is a hydrophobicstructural unit, and specifically, a structural unit containing astyrene skeleton which may have a substituent is preferable.

A styrene skeleton having a substituent refers to styrene in which thehydrogen atom on the α-position is substituted and/or part or all of thehydrogen atoms on the benzene ring are substituted with a substituent.

Examples of the substituent for the structural unit (Nx) include ahalogen atom, or a linear, branched or cyclic hydrocarbon group of 1 to20 carbon atoms optionally containing an oxygen atom, a halogen atom ora silicon atom, or a combination of the linear, branched or cyclichydrocarbon group.

Examples of the halogen atom as the substituent for the structural unit(Nx) include a fluorine atom, chlorine atom, bromine atom and iodineatom, and a fluorine atom, a chlorine atom or a bromine atom ispreferable.

The hydrocarbon group as the substituent for the structural unit (Nx)has 1 to 20 carbon atoms.

In addition, the hydrocarbon group is a linear, branched or cyclichydrocarbon group optionally containing an oxygen atom, a halogen atomor a silicon atom, or a combination of the linear, branched or cyclichydrocarbon group.

Examples of the hydrocarbon group include a linear, branched or cyclicalkyl group, or an aryl group.

The alkyl group as the hydrocarbon group preferably has 1 to 10 carbonatoms, more preferably 1 to 8 carbon atoms, and still more preferably 1to 6 carbon atoms.

The alkyl group may be a partially or fully halogenated alkyl group(halogenated alkyl group), or an alkyl group in which a carbon atomconstituting the alkyl group has been replaced by a silicon atom or anoxygen atom, such as an alkylsilyl group, an alkylsilyloxy group or analkoxy group.

The “partially halogenated alkyl group” refers to an alkyl group inwhich part of the hydrogen atoms bonded to the alkyl group aresubstituted with halogen atom(s) and the “fully halogenated alkyl group”refers to an alkyl group in which all of the hydrogen atoms bonded thealkyl group are substituted with halogen atoms. Examples of the halogenatom include a fluorine atom, chlorine atom, bromine atom and iodineatom, a fluorine atom, a chlorine atom or a bromine atom is preferable,and a fluorine atom is more preferable (that is, a fluorinated alkylgroup is preferable).

As the alkylsilyl group, a trialkylsilyl group or a trialkylsilylalkylgroup is preferable, and preferable examples thereof include atrimethylsilyl group, a trimethylsilylmethyl group, atrimethylsilylethyl group and a trimethylsilyl-n-propyl group.

As the alkylsilyloxy group, a trialkylsilyloxy group or atrialkylsilyloxyalkyl group is preferable, and preferable examplesthereof include a trimethylsilyloxy group, a trimethylsilyloxymethylgroup, a trimethylsilyloxyethyl group and a trimethylsilyloxy-n-propylgroup.

The alkoxy group preferably has 1 to 10 carbon atoms, more preferably 1to 8 carbon atoms, and still more preferably 1 to 6 carbon atoms.

The aryl group as the hydrocarbon group has 4 to 20 carbon atoms,preferably 4 to 10 carbon atom, and more preferably 6 to 10 carbonatoms.

Preferable examples of the structural unit (Nx) include a structuralunit represented by general formula (Nx-1) shown below.

In the formula, R represents a hydrogen atom, an alkyl group of 1 to 5carbon atoms or a halogenated alkyl group of 1 to 5 carbon atoms; R¹represents a halogen atom, or a linear, branched or cyclic hydrocarbongroup of 1 to 20 carbon atoms optionally containing an oxygen atom, ahalogen atom or a silicon atom, or a combination of the linear, branchedor cyclic hydrocarbon group; and n represents an integer of 0 to 5.

In formula (Nx-1), R represents a hydrogen atom, an alkyl group of 1 to5 carbon atoms or a halogenated alkyl group of 1 to 5 carbon atoms.

As the alkyl group of 1 to 5 carbon atoms for R, a linear or branchedalkyl group of 1 to 5 carbon atoms is preferable, and specific examplesthereof include a methyl group, an ethyl group, an n-propyl group, anisopropyl group, an n-butyl group, an isobutyl group, a tert-butylgroup, a pentyl group, an isopentyl group and a neopentyl group.

The halogenated alkyl group of 1 to 5 carbon atoms represented by R is agroup in which part or all of the hydrogen atoms of the aforementionedalkyl group of 1 to 5 carbon atoms have been substituted with halogenatoms. Examples of the halogen atom include a fluorine atom, a chlorineatom, a bromine atom and an iodine atom, and a fluorine atom isparticularly desirable.

As R, a hydrogen atom, an alkyl group of 1 to 5 carbon atoms or afluorinated alkyl group of 1 to 5 carbon atoms is preferable, a hydrogenatom or an alkyl group of 1 to 5 carbon atoms is more preferable, ahydrogen atom or a methyl group is still more preferable, and a hydrogenatom is most preferable.

In formula (Nx-1), R¹ represents a halogen atom, or a linear, branchedor cyclic hydrocarbon group of 1 to 20 carbon atoms optionallycontaining an oxygen atom, a halogen atom or a silicon atom, or acombination of the linear, branched or cyclic hydrocarbon group. Informula (Nx-1), R¹ is the same as defined for the substituent for theaforementioned structural unit (Nx) (a halogen atom, or a linear,branched or cyclic hydrocarbon group of 1 to 20 carbon atoms optionallycontaining an oxygen atom, a halogen atom or a silicon atom, or acombination of the linear, branched or cyclic hydrocarbon group).

Among these examples, as R¹, a linear, branched or cyclic hydrocarbongroup of 1 to 20 carbon atoms optionally containing an oxygen atom, ahalogen atom or a silicon atom, or a combination of the linear, branchedor cyclic hydrocarbon group is preferable in that a layer containing ablock copolymer to be formed on the brush layer can be satisfactorilyphase-separated.

Among these, an alkyl group of 1 to 20 carbon atoms optionallycontaining an oxygen atom or a halogen atom is preferable, an alkylgroup of 1 to 6 carbon atoms, a halogenated alkyl group of 1 to 6 carbonatoms or an alkoxy group of 1 to 6 carbon atoms is more preferable, andan alkyl group of 1 to 6 carbon atoms is most preferable.

The alkyl group for R¹ preferably has 1 to 6 carbon atoms, morepreferably 3 to 6 carbon atoms, still more preferably 3 or 4 carbonatoms, and most preferably 4 carbon atoms. As the alkyl group for alinear alkyl group or a branched alkyl group is preferable, andpreferable examples thereof include a methyl group, an ethyl group, ann-propyl group, an isopropyl group, an n-butyl group, an isobutyl groupand a tert-butyl group, more preferably an n-propyl group, an isopropylgroup, an n-butyl group, an isobutyl group or a tert-butyl group, stillmore preferably an n-butyl group, an isobutyl group or a tert-butylgroup, and most preferably a tert-butyl group.

Examples of the halogenated alkyl group for R¹ include a group in whichpart or all of the hydrogen atoms of the alkyl group for R¹ have beensubstituted with halogen. As the halogen atom, a fluorine atom is mostpreferable. The halogenated alkyl group for R¹ preferably has 1 to 6carbon atoms, more preferably 3 to 6 carbon atoms, and still morepreferably 3 or 4 carbon atoms.

The alkoxy group for R¹ preferably has 1 to 6 carbon atoms, morepreferably 1 to 4 carbon atoms, and most preferably 2 carbon atoms. Asthe alkoxy group for R¹, a linear alkoxy group or a branched alkoxygroup is preferable, and preferable examples thereof include a methoxygroup, an ethoxy group, an isopropoxy group and a t-butoxy group, and anethoxy group is most preferable.

In formula (Nx-1), n represents an integer of 0 to 5, preferably aninteger of 0 to 3, more preferably an integer of 0 to 2, still morepreferably 0 or 1, and most preferably 0.

In formula (Nx-1), the bonding position of R¹ on the benzene ring ispreferably the para position in that the phase-separation performance ofthe layer containing a block copolymer is further enhanced.

Specific examples of the structural unit (Nx) are shown below. In theformula, R^(α) represents a hydrogen atom or a methyl group.

As the structural unit (Nx), one kind of structural unit may be usedalone, or two or more kinds of structural units may be used incombination.

As the structural unit (Nx), at least one member selected from the groupconsisting of structural units represented by chemical formulae (Nx-1-1)to (Nx-1-22) is preferable, at least one member selected from the groupconsisting of structural units represented by chemical formulae (Nx-1-1)to (Nx-1-14) is more preferable, at least one member selected from thegroup consisting of structural units represented by chemical formulae(Nx-1-1) to (Nx-1-11) is still more preferable, at least one memberselected from the group consisting of structural units represented bychemical formulae (Nx-1-1) to (Nx-1-6) and (Nx-1-11) is still morepreferable, and at least one member selected from the group consistingof structural units represented by chemical formulae (Nx-1-1) to(Nx-1-3) and (Nx-1-11) is most preferable.

In the component (N), the amount of the structural unit (Nx) based onthe combined total of all structural units constituting the component(N) is preferably 95 mol % or more, more preferably 96 mol % or more,and still more preferably 97mol % or more.

When the amount of the structural unit (Nx) is at least as large as thelower limit of the above-mentioned range, the surface of the brush layerbecomes more stable, and the layer containing a block copolymer to beformed on the brush layer can be satisfactorily phase-separated.

Structural Unit (Ny)

In the present invention, the structural unit (Ny) is a hydrophilicgroup.

The structural unit (Ny) is preferably a structural derived from acrylicacid or an ester thereof which may have the hydrogen atom bonded to thecarbon atom on the α-position substituted with a substituent.

Preferable examples of the structural unit (Ny) include a structuralunit represented by general formula (Ny-1) shown below.

In the formula, R represents a hydrogen atom, an alkyl group of 1 to 5carbon atoms or a halogenated alkyl group of 1 to 5 carbon atoms; and R²represents a linear or branched hydroxyalkyl group having 1 to 20 carbonatoms.

In formula (Ny-1), R represents a hydrogen atom, an alkyl group of 1 to5 carbon atoms or a halogenated alkyl group of 1 to 5 carbon atoms. Informula (Ny-1), R is the same as defined for R in formula (Nx-1) above.

As R, a hydrogen atom, an alkyl group of 1 to 5 carbon atoms or afluorinated alkyl group of 1 to 5 carbon atoms is preferable, a hydrogenatom or an alkyl group of 1 to 5 carbon atoms is more preferable, ahydrogen atom or a methyl group is still more preferable, and a hydrogenatom is most preferable.

In formula (Ny-1), R² represents a linear or branched alkyl group of 1to 20 carbon atoms or a linear or branched hydroxyalkyl group of 1 to 20carbon atoms.

The hydroxyalkyl group for R² is an alkyl group having 1 to 20 carbonatoms, preferably 1 to 10 carbon atoms, more preferably 1 to 8 carbonatoms, still more preferably 1 to 6 carbon atoms, and most preferably 1to 4 carbon atoms, in which part or all of the hydrogen atoms of thealkyl group has been substituted with a hydroxy group. The number of thehydroxy group(s) is preferably 1 to 3, and more preferably 1 or 2.

The hydroxyalkyl group for R² may be linear or branched.

As the structural unit (Ny-1), a structural unit represented by generalformula (Ny-1-1) shown below is preferable.

In the formula, R represents a hydrogen atom, an alkyl group of 1 to 5carbon atoms or a halogenated alkyl group of 1 to 5 carbon atoms; and Y¹represents an alkyl group of 1 to 5 carbon atoms.

In general formula (Ny-1-1) R is the same as defined above. In generalformula (Ny-1-1), Y¹ represents an alkyl group of 1 to 5 carbon atomsand is the same as defined for the alkyl group of 1 to 5 carbon atomsfor R in the aforementioned formula (Nx-1). Among these, as Y¹, a methylgroup or an ethyl group is preferable, and a methyl group is morepreferable.

Specific examples of the structural unit (Ny) are shown below. In theformula, R^(α) represents a hydrogen atom or a methyl group.

As the structural unit (Ny) contained in the component (N), 1 kind ofstructural unit may be used, or 2 or more kinds of structural units maybe used in combination.

As the structural unit (Ny), at least one member selected from the groupconsisting of structural units represented by chemical formulae (Ny-1-1)to (Ny-1-3) is preferable, and a structural unit represented by chemicalformula (Ny-1-1) is most preferable.

In the component (N), the amount of the structural unit (Ny) is lessthan 5 mol %. The amount of the structural unit (Ny) is preferably 4 mol% or less, and more preferably 3 mol % or less.

In the brush composition of the present invention, by virtue of thespecific amount of the structural unit (Ny), when a brush layer isformed using the brush composition of the present invention, it isconsidered that the surface of the brush layer can be controlled to ahighly hydrophobic state.

Optional Structural Unit

The component (N) may include, in addition to the structural unit (Nx)and the structural unit (Ny), an optional structural unit (structuralunit (u3)), as long as the effects of the present invention are notimpaired. Examples of the structural unit (u3) include structural unitscopolymerizable with the monomer which provides the structural unit(Nx).

When the component (N) includes the structural unit (u3), in thecomponent (N), the amount of the structural unit (u3) based on thecombined total of all structural units constituting the component (N) ispreferably from more than 0 mol % to 25 mol %.

The weight average molecular weight (Mw) (the polystyrene equivalentvalue determined by gel permeation chromatography (GPC)) of thecomponent (N) is not particularly limited, but is preferably 1,000 to200,000, more preferably 1,500 to 200,000, and still more preferably2,000 to 150,000.

When the weight average molecular weight is no more than the upper limitof the above preferable range, the component (A) satisfactorilydissolves in an organic solvent described later, and the coatability ona substrate becomes excellent. On the other hand, when the weightaverage molecular weight is at least as large as the lower limit of theabove preferable range, the production stability of the polymericcompound becomes excellent, and the brush composition exhibits excellentcoatability on a substrate.

The molecular weight dispersity (Mw/Mn) of the component (N) is notparticularly limited, but is preferably 1.0 to 5.0, more preferably 1.0to 3.0, and most preferably 1.0 to 2.5. Here, Mn is the number averagemolecular weight.

The component (N) can be obtained, for example, by a conventionalradical polymerization or the like of the monomers corresponding witheach of the structural units, using a radical polymerization initiatorsuch as azobisisobutyronitrile (AIBN). Further, in the polymerization ofthe component (N), for example, an initiator such as CH₃—CH₂—CH(CH₃)—Limay be used.

Furthermore, in the polymerization of the component (N), for example,terminal modifier such as isobutylene sulfide may be used.

As the monomers for deriving the corresponding structural units,commercially available monomers may be used, or the monomers may besynthesized by a conventional method.

In the brush composition of the present invention, the amount of thecomponent (N) can be appropriately adjusted depending on the thicknessof the brush layer, and the like.

In the brush composition of the present invention, the amount of thecomponent (N) based on the whole solid content is preferably 70% byweight or more, more preferably 90% by weight or more, and still morepreferably 95% by weight or more.

<Optional Components>

The brush composition of the present invention may contain, in additionto the component (N), a component (optional component) other than thecomponent (N).

Acid-Generator Component (B)

The brush composition of the present invention may further contain anacid-generator component (B) (hereafter, referred to as “component(B)”). The component (B) generates acid by heat or exposure. Thecomponent (B) itself does not need to exhibit acidity, may be anycompound which is decomposed by heat or light and functions as an acid.

As the component (B), there is no particular limitation, and any of theknown acid generator components used in chemically amplified resistcompositions conventionally used in photolithography can be used.

Examples of the acid-generator component include a thermal acidgenerator that generates acid by heating, and a photoacid generator thatgenerates acid upon exposure. Examples of these acid generators arenumerous, and include onium salt acid generators such as iodonium saltsand sulfonium salts; oxime sulfonate acid generators; diazomethane acidgenerators such as bisalkyl or bisaryl sulfonyl diazomethanes andpoly(bis-sulfonyl)diazomethanes; nitrobenzylsulfonate acid generators;iminosulfonate acid generators; and disulfone acid generators.

A “thermal acid generator which generates acid by heating” refers to acomponent which generates acid upon heating preferably at 200° C. orlower. When the heating temperature is 200° C. or lower, generation ofacid may be reliably controlled.

Preferably, a component that generates acid by heating at 50 to 150° C.is used. When the preferable heating temperature is 50° C. or higher,the stability of the acid-generator component in the brush compositionbecomes satisfactory.

As the onium salt acid generator for the component (B), those in whichhave at least one anion group selected from a sulfonate anion, acarboxylate anion, a sulfonylimide anion, a bis(alkylsulfonyl)imideanion, a tris(alkylsulfonyl)methide anion and a fluoroantimonic acid ionas the anion moiety is preferable.

Further, as the cation moiety of an onium salt acid generator for thecomponent (B), a cation moiety represented by general formula (b-c1) or(b-c2) shown below is preferable.

In the formulae, R¹″ to R³″, R⁵″ and R⁶″ each independently representsan aryl group which may have a substituent, an alkyl group which mayhave a substituent or an alkenyl group which may have a substituent,provided that, in formula (b-c1), two of R¹″ to R³″ may be mutuallybonded to form a ring with the sulfur atom; and

In formula (b-c1), R¹″ to R³″ each independently represents an arylgroup which may have a substituent or an alkyl group which may have asubstituent. Two of R¹″ to R³″ may be mutually bonded to form a ringwith the sulfur atom.

Examples of the aryl group for R¹″ to R³″ include an unsubstituted arylgroup of 6 to 20 carbon atoms; a substituted aryl group in which part orall of the hydrogen atoms of the aforementioned unsubstituted aryl grouphas been substituted with an alkyl group, an alkoxy group, a halogenatom, a hydroxy group, an oxo group (═O), an aryl group, analkoxyalkyloxy group, an alkoxycarbonylalkyloxy group, —C(═O)—O—R⁶′,—O—C(═O)—R⁷′ or —O—R⁸′. Each of R⁶′, R⁷′ and R⁸′ independentlyrepresents a linear or branched saturated hydrocarbon group of 1 to 25atoms, a cyclic saturated hydrocarbon group of 3 to 20 carbon atoms or alinear or branched, aliphatic unsaturated hydrocarbon group of 2 to 5carbon atoms.

The unsubstituted aryl group for R¹″ to R³″ is preferably an aryl grouphaving 6 to 10 carbon atoms because it can be synthesized at a low cost.Specific examples thereof include a phenyl group and a naphthyl group.

The alkyl group as the substituent for the substituted aryl grouprepresented by R¹″ to R³″ is preferably an alkyl group having 1 to 5carbon atoms, and more preferably a methyl group, an ethyl group, apropyl group, an n-butyl group, or a tert-butyl group.

The alkoxy group as the substituent for the substituted aryl group ispreferably an alkoxy group having 1 to 5 carbon atoms, and morepreferably a methoxy group, an ethoxy group, an n-propoxy group, aniso-propoxy group, an n-butoxy group or a tert-butoxy group.

The halogen atom as the substituent for the substituted aryl group ispreferably a fluorine atom.

As the aryl group as the substituent for the substituted aryl group, thesame aryl groups as those described for R¹″ to R³″ can be mentioned.

Examples of alkoxyalkyloxy groups as the substituent for the substitutedaryl group include groups represented by a general formula shown below:

—O—C(R⁴⁷)(R⁴⁸)—O—R⁴⁹

In the formula, R⁴⁷ and R⁴⁸ each independently represents a hydrogenatom or a linear or branched alkyl group; and R⁴⁹ represents an alkylgroup.

The alkyl group for R⁴⁷ and R⁴⁸ preferably has 1 to 5 carbon atoms, andmay be either linear or branched. As the alkyl group, an ethyl group ora methyl group is preferable, and a methyl group is most preferable.

It is preferable that at least one of R⁴⁷ and R⁴⁸ be a hydrogen atom. Itis particularly desirable that at least one of R⁴⁷ and R⁴⁸ be a hydrogenatom, and the other be a hydrogen atom or a methyl group.

The alkyl group for R⁴⁹ preferably has 1 to 15 carbon atoms, and may belinear, branched or cyclic.

The linear or branched alkyl group for R⁴⁹ preferably has 1 to 5 carbonatoms. Examples thereof include a methyl group, an ethyl group, a propylgroup, an n-butyl group and a tert-butyl group.

The cyclic alkyl group for R⁴⁹ preferably has 4 to 15 carbon atoms, morepreferably 4 to 12, and most preferably 5 to 10. Specific examplesthereof include groups in which one or more hydrogen atoms have beenremoved from a monocycloalkane or a polycycloalkane such as abicycloalkane, tricycloalkane or tetracycloalkane, and which may or maynot be substituted with an alkyl group of 1 to 5 carbon atoms, afluorine atom or a fluorinated alkyl group. Examples of themonocycloalkane include cyclopentane and cyclohexane. Examples ofpolycycloalkanes include adamantane, norbornane, isobornane,tricyclodecane and tetracyclododecane. Among these, a group in which oneor more hydrogen atoms have been removed from adamantane is preferable.

Examples of the alkoxycarbonylalkyloxy group as the substituent for thesubstituted aryl group include groups represented by a general formulashown below:

—O—R⁵⁰—C(═O)—O—R⁵⁶

In the formula, R⁵⁰ represents a linear or branched alkylene group, andR⁵⁶ represents a tertiary alkyl group.

The linear or branched alkylene group for R⁵⁰ preferably has 1 to 5carbon atoms, and examples thereof include a methylene group, anethylene group, a trimethylene group, a tetramethylene group and a1,1-dimethylethylene group.

Examples of the tertiary alkyl group for R⁵⁶ include a2-methyl-2-adamantyl group, a 2-ethyl-2-adamantyl group, a1-methyl-1-cyclopentyl group, a 1-ethyl-1-cyclopentyl group, a1-methyl-1-cyclohexyl group, a 1-ethyl-1-cyclohexyl group, a1-(1-adamantyl)-1-methylethyl group, a 1-(1-adamantyl)-1-methylpropylgroup, a 1-(1-adamantyl)-1-methylbutyl group, a1-(1-adamantyl)-1-methylpentyl group, a 1-(1-cyclopentyl)-1-methylethylgroup, a 1-(1-cyclopentyl)-1-methylpropyl group, a1-(1-cyclopentyl)-1-methylbutyl group, a1-(1-cyclopentyl)-1-methylpentyl group, a 1-(1-cyclohexyl)-1-methylethylgroup, a 1-(1-cyclohexyl)-1-methylpropyl group, a1-(1-cyclohexyl)-1-methylbutyl group, a 1-(1-cyclohexyl)-1-methylpentylgroup, a tert-butyl group, a tert-pentyl group and a tert-hexyl group.

Further, a group in which R⁵⁶ in the group represented by theaforementioned general formula: —O—R⁵⁰—C(═O)—O—R⁵⁶ has been substitutedwith R⁵⁶′ can also be mentioned. R⁵⁶′ represents a hydrogen atom, analkyl group, a fluorinated alkyl group or an aliphatic cyclic groupwhich may contain a hetero atom.

The alkyl group for R⁵⁶′ is the same as defined for the alkyl group forthe aforementioned R⁴⁹.

Examples of the fluorinated alkyl group for R⁵⁶′ include groups in whichpart or all of the hydrogen atoms within the alkyl group for R⁴⁹ hasbeen substituted with a fluorine atom.

Examples of the aliphatic cyclic group for R⁵⁶′ which may contain ahetero atom include an aliphatic cyclic group which does not contain ahetero atom, an aliphatic cyclic group containing a hetero atom in thering structure, and an aliphatic cyclic group in which a hydrogen atomhas been substituted with a hetero atom.

As an aliphatic cyclic group for R⁵⁶′ which does not contain a heteroatom, a group in which one or more hydrogen atoms have been removed froma monocycloalkane or a polycycloalkane such as a bicycloalkane, atricycloalkane or a tetracycloalkane can be mentioned. Examples of themonocycloalkane include cyclopentane and cyclohexane. Examples ofpolycycloalkanes include adamantane, norbornane, isobornane,tricyclodecane and tetracyclododecane. Among these, a group in which oneor more hydrogen atoms have been removed from adamantane is preferable.

Specific examples of the aliphatic cyclic group for R⁵⁶′ containing ahetero atom in the ring structure include aliphatic cyclic groupsrepresented by formulae (L1) to (L6) and (S1) to (S4) below.

In the formula, Q″ represents an alkylene group of 1 to 5 carbon atoms,—O—, —S—, —O—R⁹⁴— or —S—R⁹⁵— (wherein each of R⁹⁴ and R⁹⁵ independentlyrepresents an alkylene group of 1 to 5 carbon atoms); and m represents 0or 1.

In the above formulae, the linear or branched alkylene group for Q″, R⁹⁴and R⁹⁵ preferably has 1 to 5 carbon atoms, and examples thereof includea methylene group, an ethylene group, a trimethylene group, atetramethylene group and a 1,1-dimethylethylene group.

In these aliphatic cyclic groups, part of the hydrogen atoms bonded tothe carbon atoms constituting the ring structure may be substituted witha substituent. Examples of substituents include an alkyl group, analkoxy group, a halogen atom, a halogenated alkyl group, a hydroxylgroup and an oxygen atom (═O).

As the alkyl group, an alkyl group of 1 to 5 carbon atoms is preferable,and a methyl group, an ethyl group, a propyl group, an n-butyl group ora tert-butyl group is particularly desirable.

The alkoxy group as the substituent is preferably an alkoxy group having1 to 5 carbon atoms, more preferably a methoxy group, ethoxy group,n-propoxy group, iso-propoxy group, n-butoxy group or tert-butoxy group,and most preferably a methoxy group or an ethoxy group.

Examples of the halogen atom for the substituent include a fluorineatom, a chlorine atom, a bromine atom and an iodine atom, and a fluorineatom is preferable.

As the aliphatic cyclic group for R⁵⁶′ in which a hydrogen atom has beensubstituted with a hetero atom, an aliphatic cyclic group in which ahydrogen atom has been substituted with an oxygen atom (═O) can bementioned.

In formulae —C(═O)—O—R⁶′, —O—C(═O)—R⁷′ and —O—R⁸′, R⁶′, R⁷′ and R⁸′ eachindependently represents a linear or branched saturated hydrocarbongroup of 1 to 25 atoms, a cyclic saturated hydrocarbon group of 3 to 20carbon atoms or a linear or branched, aliphatic unsaturated hydrocarbongroup of 2 to 5 carbon atoms.

The linear or branched, saturated hydrocarbon group preferably has 1 to25 carbon atoms, more preferably 1 to 15, and still more preferably 4 to10.

Examples of the linear, saturated hydrocarbon group include a methylgroup, an ethyl group, a propyl group, a butyl group, a pentyl group, ahexyl group, a heptyl group, an octyl group, a nonyl group and a decylgroup.

Examples of the branched, saturated hydrocarbon group include a 1-methylethyl group, a 1-methylpropyl group, a 2-methylpropyl group, a1-methylbutyl group, a 2-methylbutyl group, a 3-methylbutyl group, a1-ethylbutyl group, a 2-ethylbutyl group, a 1-methylpentyl group, a2-methylpentyl group, a 3-methylpentyl group and a 4-methylpentyl group,but excluding tertiary alkyl groups.

The linear or branched, saturated hydrocarbon group may have asubstituent. Examples of the substituent include an alkoxy group, ahalogen atom, a halogenated alkyl group, a hydroxyl group, an oxygenatom (═O), a cyano group and a carboxy group.

The alkoxy group as the substituent for the linear or branched saturatedhydrocarbon group is preferably an alkoxy group having 1 to 5 carbonatoms, more preferably a methoxy group, an ethoxy group, an n-propoxygroup, an iso-propoxy group, an n-butoxy group or a tert-butoxy group,and most preferably a methoxy group or an ethoxy group.

Examples of the halogen atom as the substituent for the linear orbranched, saturated alkyl group include a fluorine atom, a chlorineatom, a bromine atom and an iodine atom, and a fluorine atom ispreferable.

Example of the halogenated alkyl group as the substituent for the linearor branched, saturated hydrocarbon group includes a group in which partor all of the hydrogen atoms within the aforementioned linear orbranched, saturated hydrocarbon group have been substituted with theaforementioned halogen atoms.

The cyclic saturated hydrocarbon group of 3 to 20 carbon atoms for R⁶′,R⁷′ and R⁸′ may be either a polycyclic group or a monocyclic group, andexamples thereof include groups in which one hydrogen atom has beenremoved from a monocycloalkane, and groups in which one hydrogen atomhas been removed from a polycycloalkane (e.g., a bicycloalkane, atricycloalkane or a tetracycloalkane). More specific examples includegroups in which one hydrogen atom has been removed from amonocycloalkane such as cyclopentane, cyclohexane, cycloheptane orcyclooctane; and groups in which one or more hydrogen atoms have beenremoved from a polycycloalkane such as adamantane, norbornane,isobornane, tricyclodecane or tetracyclododecane.

The cyclic, saturated hydrocarbon group may have a substituent. Forexample, part of the carbon atoms constituting the ring within thecyclic alkyl group may be substituted with a hetero atom, or a hydrogenatom bonded to the ring within the cyclic alkyl group may be substitutedwith a substituent.

In the former example, a heterocycloalkane in which part of the carbonatoms constituting the ring within the aforementioned monocycloalkane orpolycycloalkane has been substituted with a hetero atom such as anoxygen atom, a sulfur atom or a nitrogen atom, and one hydrogen atom hasbeen removed therefrom, can be used. Further, the ring may contain anester bond (—C(═O)—O—). More specific examples include alactone-containing monocyclic group, such as a group in which onehydrogen atom has been removed from γ-butyrolactone; and alactone-containing polycyclic group, such as a group in which onehydrogen atom has been removed from a bicycloalkane, tricycloalkane ortetracycloalkane containing a lactone ring.

In the latter example, as the substituent, the same substituent groupsas those for the aforementioned linear or branched alkyl group, or analkyl group of 1 to 5 carbon atoms can be used.

Alternatively, R⁶′, R⁷′ and R⁸′ may be a combination of a linear orbranched alkyl group and a cyclic group.

Examples of the combination of a linear or branched alkyl group with acyclic alkyl group include groups in which a cyclic alkyl group as asubstituent is bonded to a linear or branched alkyl group, and groups inwhich a linear or branched alkyl group as a substituent is bonded to acyclic alkyl group.

Examples of the linear aliphatic unsaturated hydrocarbon group for R⁶′,R⁷′ and R⁸′ include a vinyl group, a propenyl group (an allyl group) anda butynyl group.

Examples of the branched aliphatic unsaturated hydrocarbon group forR⁶′, R⁷′ and R⁸′ include a 1-methylpropenyl group and a 2-methylpropenylgroup.

The aforementioned linear or branched, aliphatic unsaturated hydrocarbongroup may have a substituent.

Examples of substituents include the same substituents as those whichthe aforementioned linear or branched alkyl group may have.

Among the aforementioned examples, as R⁶′, R⁷′ and R⁸′ a linear orbranched, saturated hydrocarbon group of 1 to 15 carbon atoms or acyclic saturated hydrocarbon group of 3 to 20 carbon atoms ispreferable.

Examples of the alkyl group for R¹″ to R³″ include linear, branched orcyclic alkyl groups of 1 to 10 carbon atoms. Among these, alkyl groupsof 1 to 5 carbon atoms are preferable as the resolution becomesexcellent. Specific examples thereof include a methyl group, an ethylgroup, an n-propyl group, an isopropyl group, an n-butyl group, anisobutyl group, an n-pentyl group, a cyclopentyl group, a hexyl group, acyclohexyl group, a nonyl group, and a decyl group, and a methyl groupis most preferable because it is excellent in resolution and can besynthesized at a low cost.

The alkyl group for R¹″ to R³″ may have part or all of the hydrogenatoms substituted with an alkoxy group, a halogen atom, a hydroxy group,an oxo group (═O), an aryl group, an alkoxyalkyloxy group,alkoxycarbonylalkyloxy group, —C(═O)—O—R⁶′, —O—C(═O)—R⁷′ and —O—R⁸′. Thealkoxy group, the halogen atom, the aryl group, the alkoxyalkyloxygroup, the alkoxycarbonylalkyloxy group, —C(═O)—O—R⁶′, —O—C(═O)—R⁷′ and—O—R⁸′ are the same as defined for the substituent for the aryl grouprepresented by R¹″ to R³″.

The alkenyl group for R¹″ to R³″ preferably has 2 to 10 carbon atoms,more preferably 2 to 5, and still more preferably 2 to 4. Specificexamples thereof include a vinyl group, a propenyl group (an allylgroup), a butynyl group, a 1-methylpropenyl group and a 2-methylpropenylgroup.

When two of R¹″ to R³″ are bonded to each other to form a ring with thesulfur atom, it is preferable that the two of R¹″ to R³″ form a 3 to10-membered ring including the sulfur atom, and it is particularlydesirable that the two of to R³″ form a 5 to 7-membered ring includingthe sulfur atom.

Preferable examples of the cation moiety of the compound represented bythe aforementioned formula (b-c1) are shown below.

In the formulae, g1, g2 and g3 represent recurring numbers, wherein g1is an integer of 1 to 5, g2 is an integer of 0 to 20, and g3 is aninteger of 0 to 20.

In formula (ca-1-47), R^(d) represents a substituent. Examples of thesubstituent include those described above in the explanation of theaforementioned substituted aryl group (an alkyl group, an alkoxy group,an alkoxyalkyloxy group, an alkoxycarbonylalkyloxy group, a halogenatom, a hydroxy group, an oxo group (═O), an aryl group, —C(═O)—O—R⁶″,—O—C(═O)—R⁷″, and —O—R⁸″).

In formula (b-c2), R⁵″ and R⁶″ each independently represents an arylgroup which may have a substituent or an alkyl group which may have asubstituent.

As the aryl group for R⁵″ and R⁶″, the same aryl groups as thosedescribed above for R¹″ to R³″ can be used. The alkyl group for R⁵″ andR⁶″ is the same as defined for the alkyl group for R¹″ to R³″. Thealkenyl group for R⁵″ and R⁶″ is the same as defined for the alkenylgroup for R¹″ to R³″.

Specific examples of the cation moiety of the compound represented bygeneral formula (b-c2) include diphenyliodonium andbis(4-tert-butylphenyl)iodonium.

In the present description, an oximesulfonate acid generator is acompound having at least one group represented by general formula (B-1)shown below, and has a feature of generating acid by irradiation. Ingeneral, such oximesulfonate acid generators are widely used for achemically amplified resist composition, and can be appropriatelyselected.

In formula (B-1), each of R³¹ and R³² independently represents anorganic group.

The organic group for R³¹ and R³² refers to a group containing a carbonatom, and may include atoms other than carbon atoms (e.g., a hydrogenatom, an oxygen atom, a nitrogen atom, a sulfur atom, a halogen atom(such as a fluorine atom and a chlorine atom) and the like).

As the organic group for R³¹, a linear, branched, or cyclic alkyl groupor aryl group is preferable. The alkyl group or the aryl group may havea substituent. The substituent is not particularly limited, and examplesthereof include a fluorine atom and a linear, branched, or cyclic alkylgroup having 1 to 6 carbon atoms. The alkyl group or the aryl group “hasa substituent” means that part or all of the hydrogen atoms of the alkylgroup or the aryl group is substituted with a substituent.

The alkyl group preferably has 1 to 20 carbon atoms, more preferably 1to 10 carbon atoms, still more preferably 1 to 8 carbon atoms, stillmore preferably 1 to 6 carbon atoms, and most preferably 1 to 4 carbonatoms. As the alkyl group, a partially or completely halogenated alkylgroup (hereinafter, sometimes referred to as a “halogenated alkylgroup”) is particularly desirable. The “partially halogenated alkylgroup” refers to an alkyl group in which part of the hydrogen atoms aresubstituted with halogen atoms and the “completely halogenated alkylgroup” refers to an alkyl group in which all of the hydrogen atoms aresubstituted with halogen atoms. Examples of halogen atoms includefluorine atoms, chlorine atoms, bromine atoms and iodine atoms, andfluorine atoms are particularly desirable. In other words, thehalogenated alkyl group is preferably a fluorinated alkyl group.

The aryl group preferably has 4 to 20 carbon atoms, more preferably 4 to10 carbon atoms, and most preferably 6 to 10 carbon atoms. As the arylgroup, partially or completely halogenated aryl group is particularlydesirable. The “partially halogenated aryl group” refers to an arylgroup in which some of the hydrogen atoms are substituted with halogenatoms and the “completely halogenated aryl group” refers to an arylgroup in which all of hydrogen atoms are substituted with halogen atoms.

As R³¹, an alkyl group of 1 to 4 carbon atoms which has no substituentor a fluorinated alkyl group of 1 to 4 carbon atoms is particularlydesirable.

As the organic group for R³², a linear, branched, or cyclic alkyl group,aryl group, or cyano group is preferable. Examples of the alkyl groupand the aryl group for R³² include the same alkyl groups and aryl groupsas those described above for R³¹.

As R³², a cyano group, an alkyl group of 1 to 8 carbon atoms having nosubstituent or a fluorinated alkyl group of 1 to 8 carbon atoms isparticularly desirable.

Preferred examples of the oxime sulfonate acid generator includecompounds represented by general formula (B-2) or (B-3) shown below.

In formula (B-2), R³³ represents a cyano group, an alkyl group having nosubstituent or a halogenated alkyl group; R³⁴ represents a groupcontaining an aryl group; provided that the alkyl group or thehalogenated alkyl group for R³⁴ may be bonded with R³⁵ to form a ring;R³⁵ represents an alkyl group having no substituent or a halogenatedalkyl group.

In the formula, R³⁶ represents a cyano group, an alkyl group having nosubstituent or a halogenated alkyl group; R³⁷ represents a divalent ortrivalent aromatic hydrocarbon group; R³⁸ represents an alkyl grouphaving no substituent or a halogenated alkyl group; and p″ represents 2or 3.

In general formula (B-2), the alkyl group having no substituent or thehalogenated alkyl group for R³³ preferably has 1 to 10 carbon atoms,more preferably 1 to 8 carbon atoms, and most preferably 1 to 6 carbonatoms.

As R³³, a halogenated alkyl group is preferable, and a fluorinated alkylgroup is more preferable.

The fluorinated alkyl group for R³³ preferably has 50% or more of thehydrogen atoms thereof fluorinated, more preferably 70% or more, andmost preferably 90% or more.

Examples of the group containing an aryl group for R³⁴ include groups inwhich one hydrogen atom has been removed from an aromatic hydrocarbonring, such as a phenyl group, a biphenyl group, a fluorenyl group, anaphthyl group, an anthryl group, and a phenanthryl group, andheteroaryl groups in which some of the carbon atoms constituting thering(s) of these groups are substituted with hetero atoms such as anoxygen atom, a sulfur atom, and a nitrogen atom. Of these, a fluorenylgroup is preferable.

The group containing an aryl group for R³⁴ may have a substituent suchas an alkyl group of 1 to 10 carbon atoms, a halogenated alkyl group, oran alkoxy group. The alkyl group and halogenated alkyl group as thesubstituent preferably has 1 to 8 carbon atoms, and more preferably 1 to4 carbon atoms. Further, the halogenated alkyl group is preferably afluorinated alkyl group.

The alkyl group having no substituent or the halogenated alkyl group forR³⁵ preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbonatoms, and most preferably 1 to 6 carbon atoms.

As R³⁵, a halogenated alkyl group is preferable, and a fluorinated alkylgroup is more preferable.

In terms of enhancing the strength of the acid generated, thefluorinated alkyl group for R³⁵ preferably has 50% or more of thehydrogen atoms fluorinated, more preferably 70% or more, still morepreferably 90% or more. A completely fluorinated alkyl group in which100% of the hydrogen atoms are substituted with fluorine atoms isparticularly desirable.

In general formula (B-3), as the alkyl group having no substituent andthe halogenated alkyl group for R³⁶, the same alkyl group having nosubstituent and the halogenated alkyl group described above for R³³ canbe used.

Examples of the divalent or trivalent aromatic hydrocarbon group for R³⁷include groups in which one or two hydrogen atoms have been removed fromthe aryl group for R³⁴.

As the alkyl group having no substituent or the halogenated alkyl groupfor R³⁸, the same one as the alkyl group having no substituent or thehalogenated alkyl group for R³⁵ can be used.

p″ is preferably 2.

Specific examples of suitable oxime sulfonate acid generators includeα-(p-toluenesulfonyloxyimino)-benzyl cyanide,α-(p-chlorobenzenesulfonyloxyimino)-benzyl cyanide,α-(4-nitrobenzenesulfonyloxyimino)-benzyl cyanide,α-(4-nitro-2-trifluoromethylbenzenesulfonyloxyimino)-benzyl cyanide,α-(benzenesulfonyloxyimino)-4-chlorobenzyl cyanide,α-(benzenesulfonyloxyimino)-2,4-dichlorobenzyl cyanide,α-(benzenesulfonyloxyimino)-2,6-dichlorobenzyl cyanide,α-(benzenesulfonyloxyimino)-4-methoxybenzyl cyanide,α-(2-chlorobenzenesulfonyloxyimino)-4-methoxybenzyl cyanide,α-(benzenesulfonyloxyimino)-thien-2-yl acetonitrile,α-(4-dodecylbenzenesulfonyloxyimino)benzyl cyanide,α-└(p-toluenesulfonyloxyimino)-4-methoxyphenyl┘ acetonitrile,α-[(dodecylbenzenesulfonyloxyimino)-4-methoxyphenyl] acetonitrile,α-(tosyloxyimino)-4-thienyl cyanide,α-(methylsulfonyloxyimino)-1-cyclopentenyl acetonitrile,α-(methylsulfonyloxyimino)-1-cyclohexenyl acetonitrile,α-(methylsulfonyloxyimino)-1-cycloheptenyl acetonitrile,α-(methylsulfonyloxyimino)-1-cyclooctenyl acetonitrile,α-(trifluoromethylsulfonyloxyimino)-1-cyclopentenyl acetonitrile,α-(trifluoromethylsulfonyloxyimino)-cyclohexyl acetonitrile,α-(ethylsulfonyloxyimino)-ethyl acetonitrile,α-(propylsulfonyloxyimino)-propyl acetonitrile,α-(cyclohexylsulfonyloxyimino)-cyclopentyl acetonitrile,α-(cyclohexylsulfonyloxyimino)-cyclohexyl acetonitrile,α-(cyclohexylsulfonyloxyimino)-1-cyclopentenyl acetonitrile,α-(ethylsulfonyloxyimino)-1-cyclopentenyl acetonitrile,α-(isopropylsulfonyloxyimino)-1-cyclopentenyl acetonitrile,α-(n-butylsulfonyloxyimino)-1-cyclopentenyl acetonitrile,α-(ethylsulfonyloxyimino)-1-cyclohexenyl acetonitrile,α-(isopropylsulfonyloxyimino)-1-cyclohexenyl acetonitrile,α-(n-butylsulfonyloxyimino)-1-cyclohexenyl acetonitrile,α-(methylsulfonyloxyimino)-phenyl acetonitrile,α-(methylsulfonyloxyimino)-p-methoxyphenyl acetonitrile,α-(trifluoromethylsulfonyloxyimino)-phenyl acetonitrile,α-(trifluoromethylsulfonyloxyimino)-p-methoxyphenyl acetonitrile,α-(ethylsulfonyloxyimino)-p-methoxyphenyl acetonitrile,α-(propylsulfonyloxyimino)-p-methylphenyl acetonitrile, andα-(methylsulfonyloxyimino)-p-bromophenyl acetonitrile.

Further, oxime sulfonate acid generators disclosed in JapaneseUnexamined Patent Application, First Publication No. Hei 9-208554(Chemical Formulas 18 and 19 shown in paragraphs [0012] to [0014]) andoxime sulfonate acid generators disclosed in WO 2004/074242A2 (Examples1 to 40 described at pages 65 to 85) may be preferably used.

Furthermore, as preferable examples, the following can be used.

Of the aforementioned diazomethane acid generators, specific examples ofsuitable bisalkyl or bisaryl sulfonyl diazomethanes includebis(isopropylsulfonyl)diazomethane, bis(p-toluenesulfonyl)diazomethane,bis(1,1-dimethylethylsulfonyl)diazomethane,bis(cyclohexylsulfonyl)diazomethane, andbis(2,4-dimethylphenylsulfonyl)diazomethane.

Further, diazomethane acid generators disclosed in Japanese UnexaminedPatent Application, First Publication No. Hei 11-035551, JapaneseUnexamined Patent Application, First Publication No. Hei 11-035552 andJapanese Unexamined Patent Application, First Publication No. Hei11-035573 may be preferably used.

Furthermore, as examples of poly(bis-sulfonyl)diazomethanes, thosedisclosed in Japanese Unexamined Patent Application, First PublicationNo. Hei 11-322707, including1,3-bis(phenylsulfonyldiazomethylsulfonyl)propane,1,4-bis(phenylsulfonyldiazomethylsulfonyl)butane,1,6-bis(phenylsulfonyldiazomethylsulfonyl)hexane,1,10-bis(phenylsulfonyldiazomethylsulfonyl)decane,1,2-bis(cyclohexylsulfonyldiazomethylsulfonyl)ethane,1,3-bis(cyclohexylsulfonyldiazomethylsulfonyl)propane,1,6-bis(cyclohexylsulfonyldiazomethylsulfonyl)hexane, and1,10-bis(cyclohexylsulfonyldiazomethylsulfonyl)decane, may be given.

In the brush composition of the present invention, as the component (B),1 kind of acid generator may be used, or 2 or more kinds of acidgenerators may be used in combination.

When the brush composition contains the component (B), the amount of thecomponent (B) relative to 100 parts by weight of the component (N) ispreferably within a range from 0.5 to 30 parts by weight, and morepreferably from 1 to 20 parts by weight.

When the amount of the component (B) is within the above range, theeffects of the present invention can be satisfactorily achieved.

If desired, other miscible additives can also be added to the brushcomposition of the present invention, as long as the effects of thepresent invention are not impaired. Examples of such miscible additivesinclude additive resins for improving the performance of the brushlayer, surfactants for improving the applicability, dissolutioninhibitors, plasticizers, stabilizers, colorants, halation preventionagents, dyes, sensitizers, base amplifiers and basic compounds (e.g.,nitrogen-containing compounds, such as imidazole).

Organic Solvent (S)

The brush composition according to the present invention can be producedby dissolving the raw materials including the component (N) and thecomponent (B) and the like if desired, in an organic solvent (hereafter,referred to as “component (S)”).

The component (S) may be any organic solvent which can dissolve therespective components to give a uniform solution, and one or more kindsof any organic solvent can be appropriately selected from those whichhave been conventionally known as solvents for a film compositioncontaining a resin as a main component.

Examples of the component (S) include lactones such as γ-butyrolactone;ketones such as acetone, methyl ethyl ketone, cyclohexanone,methyl-n-pentyl ketone, methyl isopentyl ketone, and 2-heptanone;polyhydric alcohols, such as ethylene glycol, diethylene glycol,propylene glycol and dipropylene glycol; compounds having an ester bond,such as ethylene glycol monoacetate, diethylene glycol monoacetate,propylene glycol monoacetate, and dipropylene glycol monoacetate;polyhydric alcohol derivatives including compounds having an ether bond,such as a monoalkylether (e.g., monomethylether, monoethylether,monopropylether or monobutylether) or monophenylether of any of thesepolyhydric alcohols or compounds having an ester bond (among these,propylene glycol monomethyl ether acetate (PGMEA) and propylene glycolmonomethyl ether (PGME) are preferable); cyclic ethers such as dioxane;esters such as methyl lactate, ethyl lactate (EL), methyl acetate, ethylacetate, butyl acetate, methyl pyruvate, ethyl pyruvate, methylmethoxypropionate, and ethyl ethoxypropionate; and aromatic organicsolvents such as anisole, ethylbenzylether, cresylmethylether,diphenylether, dibenzylether, phenetole, butylphenylether, ethylbenzene,diethylbenzene, pentylbenzene, isopropylbenzene, toluene, xylene, cymeneand mesitylene.

The component (S) can be used individually, or in combination as a mixedsolvent.

Among these examples, as the component (S), propylene glycol monomethylether acetate (PGMEA), propylene glycol monomethyl ether (PGME),cyclohexanone and ethyl lactate (EL) are preferable.

Further, among the mixed solvents, a mixed solvent obtained by mixingPGMEA with a polar solvent is preferable. The mixing ratio (weightratio) of the mixed solvent can be appropriately determined, taking intoconsideration the compatibility of the PGMEA with the polar solvent, butis preferably in the range of 1:9 to 9:1, more preferably from 2:8 to8:2. For example, when EL is mixed as the polar solvent, the PGMEA:ELweight ratio is preferably from 1:9 to 9:1, and more preferably from 2:8to 8:2. Alternatively, when PGME is mixed as the polar solvent, thePGMEA:PGME weight ratio is preferably from 1:9 to 9:1, more preferablyfrom 2:8 to 8:2, and still more preferably 3:7 to 7:3. Alternatively,when PGME and cyclohexanone is mixed as the polar solvent, thePGMEA:(PGME+cyclohexanone) weight ratio is preferably from 1:9 to 9:1,more preferably from 2:8 to 8:2, and still more preferably 3:7 to 7:3.

Further, as the component (S), a mixed solvent of γ-butyrolactone withPGMEA, EL or the aforementioned mixed solvent of PGMEA with a polarsolvent, is also preferable. The mixing ratio (former:latter) of such amixed solvent is preferably from 70:30 to 95:5.

The amount of the component (S) is not particularly limited, and isappropriately adjusted to a concentration which enables coating of acoating solution to a substrate, depending on the thickness of thecoating film. In general, the organic solvent is used in an amount suchthat the solid content of the brush composition becomes within the rangefrom 0.1 to 20% by weight, and preferably from 0.2 to 15% by weight.

(Water Contact Angle on the Surface of the Brush Layer Formed on theSubstrate)

A brush layer formed on a substrate using the brush compositionaccording to the present invention preferably has a water contact angleof 80° or more, and more preferably 85° or more.

When the value of the contact angle is within the above preferablerange, it is considered that the adhesion of the substrate to the layercontaining a block copolymer via the brush layer becomes strong. As aresult, it is considered that the phase-separation performance of thelayer containing a block copolymer formed on the brush layer isimproved.

The water contact angle is measured, for example, by the followingsteps.

Step (1): A PGMEA solution of component (N) is applied to a substrate,so as to form a brush layer having a film thickness of less than 10 nm.

Step (2): 2 μL of water is dropped onto the surface of the brush layer,and the contact angle (static contact angle) is measured by a contactangle meter.

The brush composition according to the present invention includes aresin component (N), the resin component (N) containing a hydrophobicstructural unit (Nx) and a hydrophilic structural unit (Ny), the amountof the structural unit (Ny) within the resin component (N) being 5 mol %or less.

When the brush composition is used as a surface modifier for a substratewhich is used for phase-separation of a layer containing a blockcopolymer formed on the substrate, the adhesion of the substrate to thelayer containing a block copolymer via the brush layer formed of thebrush composition becomes strong. It is presumed that, in this manner,the phase-separation performance of the block copolymer can be improved.

Further, with respect to the brush composition, since the surface stateof the brush layer is stable, there is no need to select a neutral layermaterial which can obtain a brush layer having a surface free energy ofa predetermined value each time, depending on the kind of the blockcopolymer used. Therefore, the brush composition can be convenientlyused.

<Method of producing structure containing phase-separated structure>

A second aspect of the present invention is a method of producing astructure containing a phase-separated structure, the method including:a step of applying the brush composition of the first aspect to form abrush layer (hereafter, referred to as “step (i)”); a step of forming alayer containing a block copolymer on the brush layer (hereafter,referred to as “step (ii)”); and a step of phase-separating the layercontaining the block copolymer (hereafter, referred to as “step (iii)”).

Hereinafter, the method of producing a structure containing aphase-separated structure will be specifically described with referenceto FIG. 1. However, the present invention is not limited to theseembodiments.

FIG. 1 shows an example of one embodiment of the method of forming astructure containing a phase-separated structure according to thepresent invention.

Firstly, the brush composition of the present invention is applied to asubstrate 1, so as to form a brush layer 2 (FIG. 1 (I); step (i)).

Subsequently, to the brush layer 2 is applied a composition containing ablock copolymer (hereafter, sometimes referred to as “BCP composition”),so as to form a layer 3 containing the block copolymer (FIG. 1 (II);step (ii)).

Next, heating is conducted to perform an annealing treatment, so as tophase-separate the layer 3 containing the block copolymer into a phase 3a and a phase 3 b (FIG. 1 (III); step (iii)).

According to the production method of the present embodiment, that is,the production method including the steps (i) to (iii), a structure 3′containing a phase-separated structure is formed on the substrate 1having the brush layer 2 formed thereon.

[Step (i)]

In step (i), the brush composition is applied to a substrate 1, so as toform a brush layer 2.

By forming a brush layer 2 on the substrate 1, thehydrophilicity-hydrophobicity balance between the surface of thesubstrate 1 and the layer 3 containing the block copolymer can beobtained.

That is, by virtue of the resin component (N) contained in the brushcomposition used for the brush layer 2 having the hydrophilic structuralunit (Ny) in an amount of 5 mol % or less, the adhesion between thesubstrate 1 and the hydrophobic polymer block (b11) within the layer 3containing the block copolymer can be enhanced.

It is considered that, as a result, by phase-separation of the layer 3containing a block copolymer, a cylinder structure orientedperpendicular to the surface of the substrate 1 can be reliably formed.

The kind of the substrate 1 is not particularly limited, as long as aBCP composition can be coated thereon. Examples thereof a substrateconstituted of an organic substance, such as a metal (silicon, copper,chromium, iron, aluminum or the like), glass, titanium oxide, silica ormica; a substrate constituted of a nitride such as SiN; a substrateconstituted of an oxynitride such as SiON; and a substrate constitutedof an organic substance such as an acrylic resin, polystyrene,cellulose, cellulose acetate or phenol resin.

The size and the shape of the substrate 1 is not particularly limited.The substrate 1 does not necessarily need to have a smooth surface, anda substrate having various shapes can be appropriately selected for use.For example, substrates having various shapes can be used, such as asubstrate having a curved surface, a plate having an uneven surface, anda thin sheet.

On the surface of the substrate 1, an inorganic and/or organic film maybe provided.

As the inorganic film, an inorganic antireflection film (inorganic BARC)can be used. As the organic film, an organic antireflection film(organic BARC) can be used.

An inorganic film can be formed, for example, by coating an in organicanti-reflection film composition such as a silicon-based material on asubstrate, followed by baking.

An organic film can be formed, for example, by dissolving a resincomponent and the like for forming the film in an organic solvent toobtain an organic film-forming material, coating the organicfilm-forming material on a substrate using a spinner or the like, andbaking under heating conditions preferably in the range of 200 to 300°C. for 30 to 300 seconds, more preferably for 60 to 180 seconds. Theorganic film-forming material does not need to have susceptibility tolight or electron beam like a resist film, and the organic film-formingmaterial may or may not have such susceptibility. More specifically, aresist or a resin generally used in the production of a semiconductordevice or a liquid crystal display device can be used.

Further, it is preferable that the organic film-forming material can besubjected to etching using a block copolymer pattern formed byprocessing the layer 3, particularly dry etching, so that, by etchingthe organic film using a pattern of a block copolymer, the pattern canbe transferred to the organic film, and an organic film pattern can beformed. It is particularly desirable to use an organic film-formingmaterial which can be subjected to oxygen plasma etching or the like. Assuch an organic film-forming material, a material conventionally usedfor forming an organic film such as an organic BARC can be used.Examples of such an organic film-forming material include the ARC seriesmanufactured by NISSAN CHEMICAL INDUSTRIES, LTD., the AR seriesmanufactured by Rohm and Haas Company, and the SWK series manufacturedby Tokyo Ohka Kogyo Co., Ltd.

The method of applying the brush composition of the present invention tothe substrate 1 to form a brush layer 2 is not particularly limited, andthe brush layer 2 can be formed by a conventional method.

For example, the brush composition can be applied to the substrate 1 bya conventional method using a spinner or the like to form a coating filmon the substrate 1, followed by drying, thereby forming a brush layer 2.

The drying method of the coating film is not particularly limited,provided it can volatilize the solvent contained in the brushcomposition, and a baking method and the like are exemplified. Thebaking temperature is preferably 80° C. to 300° C., more preferably 155°C. to 270° C., still more preferably 160° C. to 250° C., and mostpreferably 170° C. to 250° C. The baking time is preferably 30 secondsto 500 seconds, and more preferably 60 seconds to 400 seconds.

The above baking time and baking temperature can be arbitrarilycombined.

The thickness of the brush layer 2 after drying of the coating film ispreferably about 10 to 100 nm, and more preferably about 40 to 90 nm.

Before forming the brush layer 2 on the substrate 1, the surface of thesubstrate 1 may be cleaned in advance. By cleaning the surface of thesubstrate 1, the coatability of the brush composition is improved.

As the cleaning treatment, a conventional method may be used, andexamples thereof include an oxygen plasma treatment, an ozone oxidationtreatment, an acid alkali treatment, and a chemical modificationtreatment.

After forming the brush layer 2, if necessary, the brush layer 2 may berinsed using a rinse liquid such as a solvent. By the rinsing,uncrosslinked portions within the brush layer 2 are removed, such thatthe affinity of the substrate for at least 1 polymer (block)constituting the block copolymer is improved, and a phase-separatedstructure having a cylinder structure oriented in a directionperpendicular to the surface of the substrate 1 can be reliably formed.

The rinse liquid may be any liquid capable of dissolving theuncrosslinked portions, and a solvent such as propylene glycolmonomethylether acetate (PGMEA), propylene glycol monomethylether(PGME), or ethyl lactate (EL), or a commercially available thinner canbe used.

After the rinsing, for volatilizing the rinse liquid, a post bake may beconducted. The temperature conditions for the post bake is preferablyfrom 80 to 300° C., more preferably from 100 to 270° C., and still morepreferably 120 to 250° C. The baking time is preferably 30 seconds to500 seconds, and more preferably 60 seconds to 240 seconds. Thethickness of the brush layer 2 after the post bake is preferably about 1to 10 nm, and more preferably about 2 to 7 nm.

[Step (ii)]

In step (ii), on the brush layer 2, a layer 3 containing a blockcopolymer having a plurality of blocks bonded is formed. As the blockcopolymer, a block copolymer in which the aforementioned hydrophobicpolymer block (b11) and the hydrophilic polymer block (b21) are bondedmay be used.

The method of forming the layer 3 on the brush layer 2 is notparticularly limited, and examples thereof include a method in which aBCP composition is applied to the brush layer 2 by a conventional methodusing spin-coating or a spinner, followed by drying. The details of theBCP composition will be described later.

The layer 3 may have a thickness satisfactory for phase-separation tooccur. In consideration of the kind of the substrate 1, the structureperiod size of the phase-separated structure to be formed, and theuniformity of the nanostructure, the thickness is preferably 20 to 100nm, and more preferably 30 to 80 nm.

For example, in the case where the substrate 1 is a Cu substrate, thethickness of the layer 3 is preferably 10 to 100 nm, and more preferably30 to 80 nm.

[Step (iii)]

Step (iii), the layer 3 containing a block copolymer is phase-separated.

By heating the substrate 1 after step (ii) to conduct the annealtreatment, the block copolymer is selectively removed, such that aphase-separated structure in which at least part of the surface of thesubstrate 1 is exposed is formed. That is, on the substrate 1, astructure 3′ containing a phase-separated structure in which phase 3 aand phase 3 b are phase separated is produced.

The anneal treatment is preferably conducted at a temperature at leastas high as the glass transition temperature of the block copolymer usedand lower than the heat decomposition temperature. For example, in thecase where the block copolymer is a polystyrene-polymethacrylate(PS-PMMA) block copolymer (weight average molecular weight: 5,000 to100,000), 180 to 270° C. is preferable. The heating time is preferably30 to 3,600 seconds.

Further, the anneal treatment is preferably conducted in a low reactivegas such as nitrogen.

By the method of producing a structure containing a phase-separatedstructure according to the present invention described heretofore, thephase-separation performance of the block copolymer can be enhanced, anda fine structure with a good shape can be formed, as compared toconventional lithography techniques. In addition, on the surface of thesubstrate, a substrate provided with a nanostructure which has theposition and the orientation designed more freely can be produced. Forexample, the formed structure has high adhesion to the substrate, and islikely to have a phase-separated structure with a cylinder structureoriented in a direction perpendicular to the surface of the substrate.

[Optional Step]

The method of forming a structure containing a phase-separated structureaccording to the present invention is not limited to the aboveembodiment, and may include a step (optional step) other than steps (i)to (iii).

Examples of the optional steps include a step of selectively removing aphase constituted of at least one block of the plurality of blocksconstituting the block copolymer contained in the layer containing theblock copolymer (hereafter, referred to as “step (iv)”), and a guidepattern formation step.

Step (iv)

In step (iv), from the layer containing a block copolymer formed on thebrush layer, a phase constituted of at least one block of the pluralityof blocks constituting the block copolymer is selectively removed. Inthis manner, a fine pattern (polymeric nanostructure) can be formed.

Examples of the method of selectively removing a phase constituted of ablock include a method in which an oxygen plasma treatment or a hydrogenplasma treatment is conducted on the layer containing a block copolymer.

Hereafter, among the blocks constituting the block copolymer, a blockwhich is not selectively removed is referred to as “block P_(A)”, and ablock to be selectively removed is referred to as “block P_(B)”. Forexample, after the phase separation of a layer containing a PS-PMMAblock copolymer, by subjecting the layer to an oxygen plasma treatmentor a hydrogen plasma treatment, the phase of PMMA is selectivelyremoved. In such a case, the PS portion is the block P_(A), and the PMMAportion is the block P_(B).

FIG. 2 shows an example of one embodiment of step (iv).

In the embodiment shown in FIG. 2, by conducting oxygen plasma treatmenton the structure 3′ produced on the substrate 1 in step (iii), the phase3 a is selectively removed, and a pattern (polymeric nanostructure)constituted of phases 3 b separated from each other is formed. In thiscase, the phase 3 b is the phase constituted of the block P_(A), and thephase 3 a is the phase constituted of the block P_(B).

The substrate 1 having a pattern formed by phase-separation of the layer3 containing the block copolymer as described above may be used as itis, or may be further heated to modify the shape of the pattern(polymeric nanostructure) on the substrate 1.

The heat treatment is preferably conducted at a temperature at least ashigh as the glass transition temperature of the block copolymer used andlower than the heat decomposition temperature. Further, the heating ispreferably conducted in a low reactive gas such as nitrogen.

Guide Pattern Forming Step

In the method of forming a structure containing a phase-separatedstructure according to the present invention, between step (i) and step(ii), a step of forming a guide pattern on the brush layer (guidepattern forming step) may be included. In this manner, it becomespossible to control the arrangement of the phase-separated structure.

For example, in the case of a block copolymer where a randomfingerprint-patterned phase separation structure is formed without usinga guide pattern, by providing a trench pattern of a resist film on thesurface of the brush layer, a phase separation structure arranged alongthe trench can be obtained. The guide pattern can be provided on thebrush layer 2 in accordance with the above-described principle. Further,when the surface of the guide pattern has affinity for any of thepolymers constituting the block copolymer, a phase separation structurehaving a cylinder structure arranged in the perpendicular direction ofthe surface of the substrate can be more reliably formed.

The guide pattern can be formed, for example, using a resistcomposition.

The resist composition for forming the guide pattern can beappropriately selected from resist compositions or a modified productthereof typically used for forming a resist pattern which have affinityfor any of the polymers constituting the block copolymer. The resistcomposition may be either a positive resist composition capable offorming a positive pattern in which exposed portions of the resist filmare dissolved and removed, or a negative resist pattern capable offorming a negative pattern in which unexposed portions of the resistfilm are dissolved and removed, but a negative resist composition ispreferable. As the negative resist composition, for example, a resistcomposition containing an acid generator and a base component whichexhibits decreased solubility in an organic solvent-containingdeveloping solution under action of acid, wherein the base componentcontains a resin component having a structural unit which is decomposedby action of acid to exhibit increased polarity, is preferable.

When the BCP composition is cast onto the brush layer having the guidepattern formed thereon, an anneal treatment is conducted to causephase-separation. Therefore, the resist pattern for forming a guidepattern is preferably capable of forming a resist film which exhibitssolvent resistance and heat resistance.

Composition Containing a Block Copolymer (BCP Composition)

A BCP composition can be prepared by dissolving the above blockcopolymer in an organic development. The organic solvent is the same asdefined for the organic solvent usable for the brush composition.

The amount of the organic solvent in the BCP composition is notparticularly limited, and is adjusted appropriately to a concentrationthat enables application of a coating solution depending on thethickness of the coating film. In general, the organic solvent is usedin an amount that yields a solid content for the block copolymer that iswithin a range from 0.2 to 70% by weight, and preferably from 0.2 to 50%by weight.

If desired, in addition to the block copolymer and the organic solvent,other miscible additives can also be added to the BCP composition.Examples of such miscible additives include additive resins forimproving the performance of the layer of the brush layer, surfactantsfor improving the applicability, dissolution inhibitors, plasticizers,stabilizers, colorants, halation prevention agents, dyes, sensitizers,base amplifiers and basic compounds.

EXAMPLES

As follows is a description of examples of the present invention,although the scope of the present invention is by no way limited bythese examples.

<Preparation of Brush Composition>

Examples 1 to 5, Comparative Examples 1 to 3

Polymeric compounds 1 and 2 were synthesized by conventional radicalpolymerization.

Then, each of the polymeric compounds 1 and 2 were dissolved inpropylene glycol monomethyl ether acetate (PGMEA), so as to prepare thebrush compositions (solid content: 1.2 wt %) of the following examples(Examples 1 to 5 and Comparative Examples 1 to 3).

TABLE 1 Resin component Organic (N) solvent (S) Example 1 (N)-4 (S)-1[100] [8230] Example 2 (N)-5 (S)-1 [100] [8230] Example 3 (N)-6 (S)-1[100] [8230] Example 4 (N)-7 (S)-1 [100] [8230] Example 5 (N)-8 (S)-1[100] [8230]

TABLE 2 Resin component Organic (N) solvent (S) Comparative (N)-2 (S)-1Example 1 [100] [8230] Comparative (N)-1 (S)-1 Example 2 [100] [8230]Comparative (N)-3 (S)-1 Example 3 [100] [8230]

In Tables 1 and 2, the reference characters indicate the following. Thevalues in brackets [ ] indicate the amount (in terms of parts by weight)of the component added.

(N)-1:Polymeric compound 1 shown below. The compositional ratio of thecopolymer (the molar ratio of the respective structural units in thepolymeric compound) as determined by ¹³C-NMR was x/y/z=82/12/6; theweight average molecular weight (Mw) determined by the polystyreneequivalent value as measured by GPC was 25,000; and the polydispersity(Mw/Mn) was 1.65.

(N)-2:Polymeric compound 2 shown below. The compositional ratio of thecopolymer (the molar ratio of the respective structural units in thepolymeric compound) as determined by ¹³C-NMR was x/y=93/7; the weightaverage molecular weight (Mw) determined by the polystyrene equivalentvalue as measured by GPC was 25,000; and the polydispersity (Mw/Mn) was1.64.

(N)-3:Polymeric compound 2 shown below. The compositional ratio of thecopolymer (the molar ratio of the respective structural units in thepolymeric compound) as determined by ¹³C-NMR was x/y=94/6; the weightaverage molecular weight (Mw) determined by the polystyrene equivalentvalue as measured by GPC was 25,000; and the polydispersity (Mw/Mn) was1.64.

(N)-4:Polymeric compound 2 shown below. The compositional ratio of thecopolymer (the molar ratio of the respective structural units in thepolymeric compound) as determined by ¹³C-NMR was x/y=95/5; the weightaverage molecular weight (Mw) determined by the polystyrene equivalentvalue as measured by GPC was 25,000; and the polydispersity (Mw/Mn) was1.64.

(N)-5:Polymeric compound 2 shown below. The compositional ratio of thecopolymer (the molar ratio of the respective structural units in thepolymeric compound) as determined by ¹³C-NMR was x/y=96/4; the weightaverage molecular weight (Mw) determined by the polystyrene equivalentvalue as measured by GPC was 25,000; and the polydispersity (Mw/Mn) was1.67.

(N)-6:Polymeric compound 2 shown below. The compositional ratio of thecopolymer (the molar ratio of the respective structural units in thepolymeric compound) as determined by ¹³C-NMR was x/y=97/3; the weightaverage molecular weight (Mw) determined by the polystyrene equivalentvalue as measured by GPC was 25,000; and the polydispersity (Mw/Mn) was1.67.

(N)-7:Polymeric compound 2 shown below. The compositional ratio of thecopolymer (the molar ratio of the respective structural units in thepolymeric compound) as determined by ¹³C-NMR was x/y=98/2; the weightaverage molecular weight (Mw) determined by the polystyrene equivalentvalue as measured by GPC was 25,000; and the polydispersity (Mw/Mn) was1.68.

(N)-8:Polymeric compound 2 shown below. The compositional ratio of thecopolymer (the molar ratio of the respective structural units in thepolymeric compound) as determined by ¹³C-NMR was x/y=99/1; the weightaverage molecular weight (Mw) determined by the polystyrene equivalentvalue as measured by GPC was 25,000; and the polydispersity (Mw/Mn) was1.67.

(S)-1: propyleneglycol monomethyletheracetate (PGMEA).

(Production of Structure Containing Phase-Separated Structure)

[Step (i)]

Subsequently, each of the brush compositions shown in Tables 1 and 2(Examples 1 to 5 and Comparative Examples 1 to 3) was applied to an8-inch silicon wafer using a spinner, followed by baking and drying at abaking temperature and a baking time shown in Table 3, so as to form abrush layer.

The brush layer was rinsed with OK73 thinner (product name; manufacturedby Tokyo Ohka Kogyo Co., Ltd.), so as to remove the uncrosslinkedportions and the like of the random copolymer. Then, baking wasconducted at 250° C. for 60 seconds. [Water Contact Angle on the Surfaceof the Brush Layer]

A water droplet was dripped onto the surface of the brush layer, andDROP MASTER-700 apparatus (a product name, manufactured by KyowaInterface Science Co. Ltd.) was used to measure the contact angle(static contact angle) (contact :angle measurement: water 2 μL). Themeasured value is indicated under “contact angle(°)” in Table 3.

[Step (ii)]

Subsequently, a PGMEA solution of a PS-PMMA block copolymer (PS/PMMAcompositional ratio (molar ratio)=55/45; Mw=42,400; Mw/Mn=1.07;period=26 nm) (block copolymer concentration: 2 wt %) was spin-coated(number of rotation: 1,500 rpm; 60 seconds) to cover the brush layerformed on the organic anti-reflection film.

Then, the substrate having the PGMEA solution of the PS-PMMA blockcopolymer coated thereon was baked and dried at 90° C. for 60 seconds,so as to form a PS-PMMA block copolymer layer having a film thickness of30 nm.

[Step (iii)]

Next, in a nitrogen gas stream, an anneal treatment was conducted byheating at 210° C. for 300 seconds, so as to phase-separate the PS-PMMAblock copolymer layer into a phase constituted of PS and a phaseconstituted of PMMA, thereby forming a phase-separated structure.

As a result, in each of the examples, a structure containing aphase-separated structure was formed on the brush layer. In the case ofusing the brush compositions of Examples 1 to 5, a pattern in which botha perpendicular vertical cylinder pattern and a horizontal cylinderpattern were present was formed. In the case of using the brushcompositions of Comparative Examples 1 to 3, a perpendicular verticalcylinder pattern was formed.

[Step (iv)]

An oxygen plasma treatment (200 mL/min, 40 Pa, 40° C., 200 W, 20seconds) was conducted on the silicon (Si) wafer having thephase-separated structure formed thereon using TCA-3822 (manufactured byTokyo Ohka Kogyo Co., Ltd.), so as to selectively remove the phaseconstituted of PMMA.

[Evaluation of Phase-Separation Performance]

The surface of the obtained substrate (phase-separation state) wasobserved with a scanning electron microscope (SEM) (CG5000 manufacturedby Hitachi High-Technologies).

As a result of the observation, the case where a pattern in which both aperpendicular vertical cylinder pattern and a horizontal cylinderpattern were present with more horizontal cylinders was observed wasevaluated “A”, the case where a pattern in which both a perpendicularvertical cylinder pattern and a horizontal cylinder pattern were presentwas observed was evaluated “B”, and the case where only a perpendicularvertical cylinder pattern was observed was evaluated The results areindicated under “phase-separation performance” in Table 3.

In the present specification, formation of a horizontal cylinder patternindicates that the brush composition has a higher affinity for thehydrophobic polymer block.

TABLE 3 Baking Baking Contact temperature time angle Phase-separation (°C.) (Seconds) (°) performance Example 1 210 60 87.7 B Example 2 210 6088.0 B Example 3 210 60 87.7 A Example 4 210 60 87.7 A Example 5 210 6087.8 A Comparative 210 60 82.5 C Example 1 Comparative 210 60 82.5 CExample 2 Comparative 210 60 84.2 C Example 3

From the results shown in Table 3, it was confirmed that, in the caseswhere the brush compositions of Examples 1 to 5 adopting the presentinvention were used, the phase-separation performance of the blockcopolymer can be improved, as compared to the cases where the brushcompositions of Comparative Examples 1 to 3 outside the scope of thepresent invention were used.

In addition, with respect to the brush compositions of Examples 1 to 5,it was confirmed that, in the production of a structure containing aphase-separated structure, the water contact angle is large, andhorizontal cylinder pattern was formed. Therefore, it was confirmed thatthe brush compositions of Examples 1 to 5 has a higher affinity for thehydrophobic polymer block.

In the present examples, the phase-separation performance is tested inthe case where the brush composition of the present invention is appliedto a substrate, and a block copolymer is applied to the brushcomposition. The aim of the test is to test the affinity for the blockcopolymer, and by no means limit other applications of the brushcomposition. For example, even in the case where the brush compositionof the present invention is applied to a substrate to form a brushlayer, and a guide pattern is formed on the brush layer using a resistcomposition or the like, it is considered that the phase-separationperformance can be improved as compared to the cases where the brushcompositions of Comparative Examples 1 to 3 outside the scope of thepresent invention are used.

While preferred embodiments of the invention have been described andillustrated above, it should be understood that these are exemplary ofthe invention and are not to be considered as limiting. Additions,omissions, substitutions, and other modifications can be made withoutdeparting from the spirit or scope of the present invention.Accordingly, the invention is not to be considered as being limited bythe foregoing description, and is only limited by the scope of theappended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

1: Substrate

2: Brush layer

3: Layer

3 a: Phase

3 b: Phase

1-3. (canceled)
 4. A method of producing a structure containing aphase-separated structure, the method comprising: applying a brushcomposition to a substrate to form a brush layer; forming a layercontaining a block copolymer on the brush layer; and phase-separatingthe layer containing the block copolymer wherein the brush compositioncomprises a resin component (N) containing a hydrophobic structural unit(Nx) and a hydrophilic structural unit (Ny), and wherein the amount ofthe structural unit (Ny) within the resin component (N) is 5 mol % orless.
 5. The method according to claim 4, wherein the structural unit(Nx) is a structural unit represented by general formula (Nx-1), and thestructural unit (Ny) is a structural unit represented by general formula(Ny-1):

in formula (Nx-1), R represents a hydrogen atom, an alkyl group of 1 to5 carbon atoms or a halogenated alkyl group of 1 to 5 carbon atoms; R¹represents a halogen atom, or a linear, branched or cyclic hydrocarbongroup of 1 to 20 carbon atoms optionally containing an oxygen atom, ahalogen atom or a silicon atom, or a combination of the linear, branchedor cyclic hydrocarbon group; and n represents an integer of 0 to 5; informula (Ny-1), R represents a hydrogen atom, an alkyl group of 1 to 5carbon atoms or a halogenated alkyl group of 1 to 5 carbon atoms; and R²represents a linear or branched hydroxyalkyl group having 1 to 20 carbonatoms.
 6. The method according to claim 5, wherein general formula(Ny-1) is represented by general formula (Ny-1-1) shown below:

wherein R represents a hydrogen atom, an alkyl group of 1 to 5 carbonatoms or a halogenated alkyl group of 1 to 5 carbon atoms; and Y¹represents an alkyl group of 1 to 5 carbon atoms.
 7. The methodaccording to claim 5, wherein the resin component (N) consists of thehydrophobic structural unit (Nx) and the hydrophilic structural unit(Ny).
 8. The method according to claim 6, wherein the resin component(N) consists of the hydrophobic structural unit (Nx) and the hydrophilicstructural unit (Ny).
 9. The method according to claim 4, wherein theblock copolymer is a polystyrene-polymethyl methacrylate (PS-PMMA) blockcopolymer.
 10. The method according to claim 5, wherein the blockcopolymer is a polystyrene-polymethyl methacrylate (PS-PMMA) blockcopolymer.
 11. The method according to claim 6, wherein the blockcopolymer is a polystyrene-polymethyl methacrylate (PS-PMMA) blockcopolymer.
 12. The method according to claim 7, wherein the blockcopolymer is a polystyrene-polymethyl methacrylate (PS-PMMA) blockcopolymer.
 13. The method according to claim 8, wherein the blockcopolymer is a polystyrene-polymethyl methacrylate (PS-PMMA) blockcopolymer.